In magnetic resonance elastography (MRE), mechanically-induced motion in tissue is estimated from a time-encoded series of phase-contrast images. For steady-state MRE, relevant motion information is encoded within the first temporal harmonic signal (i.e., Fourier coefficient) of this image series. With an estimate of this quantity and knowledge of certain scan parameters, quantitative spatial maps of tissue stiffness can be constructed. The accuracy of the maps is intrinsically dependent on the accuracy of estimated temporal harmonic signal, which, in turn, depends on the quality of the phase-contrast images. Often the phase-contrast images can be of a low signal-to-noise ratio (SNR) or include phase wrapping. This leads to inaccurate estimates of the harmonic signals and inaccurate maps of tissue stiffness.
It would be desirable to have a system and method for generating spatial maps from temporal harmonic signals of increased accuracy despite a low SNR or phase wrapping in the phase-contrast images.